Microplastics Contamination in Commercial Green Mussels from Selected Wet Markets in Thailand

Microplastic contamination in green mussels (Perna viridis Linnaeus, 1858) from traditional seafood markets in Jakarta, Indonesia, and an evaluation of potential hazards

Marine organisms, especially mussels, can efficiently take up microplastics (MPs) through their filtration processes. This study evaluated the characteristics of MPs in green mussels (Perna viridis) sold at traditional seafood markets in Jakarta, Indonesia. The polymers of MPs were examined using Fourier Transform Infrared spectroscopy, while the chemical components of MPs in green mussels were analyzed using Gas Chromatography-Mass Spectrometry. The MPs identified in green mussels sold at traditional seafood markets in Jakarta are predominantly of fiber type, display a black coloration, and measure <100 μm in size. The density of these microplastics in green mussels is uniform across all traditional markets. The concentration of microplastics in green mussels correlates positively with the length of the green mussel shell. The average annual consumption of mussel products by people in Jakarta was 11,170 items/year/person. Green mussels from Jakarta exhibited a significantly elevated polymer hazard index (III), indicating the presence of polymers categorized as high risk. Certain plasticizers (phthalates) and specific additive chemicals (phenol, butylated hydroxytoluene, and hexadecanamide) were also present in green mussels sourced from traditional markets in Jakarta. These substances are toxic and have a negative impact on both aquatic life and humans.

Effects of Vibrio vulnificus and Microcystis aeruginosa co-exposures on microplastic accumulation and depuration in the Eastern Oyster (Crassostrea virginica)

Microplastics are ubiquitous in the aquatic environment, and bivalves such as the Eastern oyster (Crassostrea virginica) can accumulate these particles directly from the water column. Bivalves are concurrently exposed to pathogenic and toxin-producing bacteria, including Vibrio spp. and Microcystis spp., which have been shown to adversely impact filtration rates. Exposure to these bacteria could thus affect oysters' ability to accumulate and depurate microplastics. As climate change creates conditions that favor Vibrio spp. and Microcystis spp. growth in estuaries, it is increasingly important to understand how these co-occurring biotic stressors influence microplastic contamination in bivalves. The objective of this study was to examine how co-exposures to Vibrio vulnificus and Microcystis aeruginosa influence microplastic accumulation and depuration in Eastern oysters. Oysters were exposed to nylon microplastics (5000 particles L-1) and either V. vulnificus, M. aeruginosa, or both species (104 colony-forming units or cells mL-1, respectively) and sampled over time up to 96 h. Following exposure, remaining oysters were allowed to depurate in clean seawater and sampled over time for up to 96 h. Microplastic concentrations in oysters were quantified and compared among treatments, and rate constants for uptake (ku) and depuration (kd) were calculated using nonlinear regression and two-compartment kinetic models. Overall, microplastic concentrations in oysters exposed to V. vulnificus (X‾ = 2.885 ± 0.350 (SE) particles g-1 w.w.) and V. vulnificus with M. aeruginosa (X‾ = 3.089 ± 0.481 particles g-1 w.w.) were higher than oysters exposed to M. aeruginosa (X‾ = 1.540 ± 0.235 particles g-1 w.w.) and to microplastics alone (X‾ = 1.599 ± 0.208 particles g-1 w.w.). Characterizing microplastic accumulation and depuration in oysters co-exposed to these biotic stressors is an important first step in understanding how contaminant loads in bivalves can change. With this research, the efficacy of depuration for commonly-consumed seafood species can be estimated.

Microplastic ingestion in mussels from the East Mediterranean Sea: Exploring its impacts in nature and controlled conditions

Microplastic ingestion poses a significant concern for a plethora of marine organisms due to its widespread presence in marine ecosystems. Despite growing scientific interest, the effects on marine biota are not yet well understood. This study investigates the ingestion of microplastics (MPs) by mussels from various marine environments and assesses the associated effects that can be induced by MPs and associated toxic chemicals. Biomarkers of oxidative stress (catalase, lipid peroxidation), biotransformation (glutathione S-transferase), genotoxicity (micronuclei frequency) and neurotoxicity (acetylcholinesterase) were employed. Mussels, considered reliable bioindicators of MPs pollution, were sampled by hand from diverse locations under varied anthropogenic pressures, including a highly touristic Marine Protected Area (MPA) in the Ionian Sea, a mussel farm and a fish farm in the Aegean Sea. The results revealed the highest MP ingestion in mussels from the fish farm [0.21 ± 0.04 (SE) MPs/g or 0.63 ± 0.12 (SE) MPs/Ind.], likely due to plastic aquaculture equipment use. Stereoscopic observation revealed fibers, as the predominant shape of ingested MPs across all sites, and μFTIR polymer identification revealed the presence of various types, with polyethylene (PE) and polyamide (PA) being the most abundant. Significant physiological alterations in mussels related to MP ingestion levels were observed through biomarkers indicative of oxidative stress and biotransformation, as well as the Integrated Biomarker Response (IBR index). However, laboratory experiments with mussels exposed to controlled increasing PE concentrations for four weeks, did not show significant effects triggered by the PE ingestion, possibly indicating other environmental factors, such as contaminants from aquaculture environments, may influence biomarker levels in the field. Despite the observed effects, MP ingestion rates in mussels from the field were relatively low compared to other studies. Future research should continue to investigate the interactions between MPs and marine organisms in diverse environments to better understand and mitigate their impacts.

Critical review on unveiling the toxic and recalcitrant effects of microplastics in aquatic ecosystems and their degradation by microbes

Production of synthetic plastic obtained from fossil fuels are considered as a constantly growing problem and lack in the management of plastic waste has led to severe microplastic pollution in the aquatic ecosystem. Plastic particles less than 5mm are termed as microplastics (MPs), these are pervasive in water and soil, it can also withstand longer period of time with high durability. It can be broken down into smaller particles and can be adsorbed by various life-forms. Most marine organisms tend to consume plastic debris that can be accumulated easily into the vertebrates, invertebrates and planktonic entities. Often these plastic particles surpass the food chain, resulting in the damage of various organs and inhibiting the uptake of food due to the accumulation of microplastics. In this review, the physical and chemical properties of microplastics, as well as their effects on the environment and toxicity of their chemical constituents are discussed. In addition, the paper also sheds light on the potential of microorganisms such as bacteria, fungi, and algae which play a pivotal role in the process of microplastics degradation. The mechanism of microbial degradation, the factors that affect degradation, and the current advancements in genetic and metabolic engineering of microbes to promote degradation are also summarized. The paper also provides information on the bacterial, algal and fungal degradation mechanism including the possible enzymes involved in microplastic degradation. It also investigates the difficulties, limitations, and potential developments that may occur in the field of microbial microplastic degradation.

Evaluation of microplastic bioaccumulation capacity of mussel (Perna viridis) and surrounding environment in the North coast of Vietnam

This study aimed to identify the presence of microplastics in green mussels (Perna viridis), surface seawater, and beach sediment on the North Coast of Vietnam. The average concentration of MPs in mussels was 3.67 ± 1.20 MPs/g wet weight and 25.05 ± 5.36 MPs/individual. Regarding surface seawater and beach sediments, the MPs concentration was found at 88.00 ± 30.88 MPs/L and 4800 ± 1776 MPs/kg dry weight, respectively. The dominant microplastics shape was fragment with the fractions ranging from 69.86 to 82.41 %. In addition, the size distribution of MPs was mostly in the range of smaller than 50 μm and 1-150 μm (34.17 % and 45.62 % in mussels; 29.65 % and 43.20 % in surface seawater and 40.22 % and 39.40 % in beach sediment, respectively). Polyethylene terephthalate was the major polymer types 49.93-58.44 % of the detected MPs. The risk assessment results based on the polymer types indicated a warning level in several sites.

Microplastic contamination in Thai vinegar crabs (Episesarma mederi), giant mudskippers (Periophthalmodon schlosseri), and their surrounding environment from the Bang Pu mangrove forests, Samut Prakan province, Thailand

The mangrove ecosystem becomes the receptacle for both land- and marine-based plastic waste. This study examines MPs contamination in the Bang Pu mangrove forests (BPMFs) in the inner Gulf of Thailand. For this, Thai vinegar crabs (TVCs) (Episesarma mederi) and giant mudskippers (GMs) (Periophthalmodon schlosseri) were investigated with their surrounding environment in both rainy and dry seasons. Two-step digestion was employed for biota samples. MPs abundance ranged from 7.5 ± 3.8 to 15.9 ± 6.7 items/individual in TVCs and 6.2 ± 5.0 to 10.6 ± 2.6 items/individual in GMs. MPs in small-size ranges (<0.5 mm) were predominant. Fiber MPs were mostly detected in the rainy season. Most MPs were transparent with polyethylene and polypropylene as dominant polymers in all samples. Bioaccumulation was not observed in GMs. The results indicated the imperiled status of MPs contamination in TVCs and GMs with contaminated surrounding environments.

A new quantitative insight: Interaction of polyethylene microplastics with soil - microbiome - crop

In this study, the interaction between primary/secondary PE MPs and soil - microbiome - crop complex system and PE MPs enrichment behavior in crops were studied by using the self-developed quantitative characterization method of Eu-MPs and in situ zymography. The results demonstrated for the first time the enrichment effect of micron-sized PE (> 10 µm) in crops, manifested as roots>leaves>stems. Primary PE MPs significantly increased soil TN, TC, SOM and β-glu activity and inhibited Phos activity. Age-PE MPs significantly reduced soil TN, TP, β-glu and Phos activities and also have significant inhibitory effects on plant height, stem diameter, and leaf dry weight of maize. Age-PE MPs significantly affected soil microbial diversity, mainly caused by bacterial genera such as UTCFX1, Sphingomonas, Subgroup-6 and Gemmatimonas. Age-PE MPs also affected some metabolism related to microbial community composition and maize growth, including Glycerolipid, Citrate cycle (TCA cycle), C5-Branched dibasic acid, Arginine and proline, Tyrosine metabolism, pentose phosphate pathway, Valine, leucine and isoleucine biosynthesis. These research results indicated that the PE MPs, which are widely present in farmland soils, can affect crop growth, soil microbial community and metabolic function after aging, thus affecting agroecosystems and terrestrial biodiversity.

Application of Infrared and Near-Infrared Microspectroscopy to Microplastic Human Exposure Measurements

Microplastic pollution is a global issue for the environment and human health. The potential for human exposure to microplastic through drinking water, dust, food, and air raises concern, since experimental in vitro and in vivo toxicology studies suggest there is a level of hazard associated with high microplastic concentrations. However, to infer the likelihood of hazards manifesting in the human population, a robust understanding of exposure concentrations is needed. Infrared and near-infrared microspectroscopies have routinely been used to analyze microplastic in different exposure matrices (air, dust, food, and water), with technological advances coupling multivariate and machine learning algorithms to spectral data. This focal point article will highlight the application of infrared and Raman modes of spectroscopy to detect, characterize, and quantify microplastic particles, with a focus on human exposure to microplastic. Methodologies and state-of-the-art approaches will be reported and potential confounding variables and challenges in microplastic analysis discussed. The article provides an up-to-date review of the literature on microplastic exposure measurement using (near) infrared spectroscopies as an analytical tool, highlighting the recent advances in this rapidly advancing field.

Preliminary survey on the occurrence of microplastics in bivalve mollusks marketed in Apulian fish markets

Microplastics (MPs) are a relevant threat to food safety because they are ingested by humans through various foods. Bivalves are at high risk of microplastic contamination due to their filter-feeding mechanism and pose a risk to consumers as they are ingested whole. In this work, microplastics were detected, quantified, identified, and classified in samples of mussels (Mytilus galloprovincialis) and oysters (Crassostrea gigas) marketed in the Apulia region. The total number of plastic debris was 789 particles in the mussel samples and 270 particles in the oyster samples, with size ranging from 10 to 7350 μm. Fragments with size within the category of 5-500 μm were the predominant findings in both species, with blue as the predominant color in mussels and transparent in oysters; most of the debris was polyamide and nylon polymers in the mussels and chlorinated polypropylene in the oysters. These results show that mussel and oyster samples purchased at fish markets are contaminated with microplastics. The sources may be diverse and further studies are needed to assess the impact of the marketing stage on microplastic contamination in bivalves to better define the human risk assessment associated with microplastic exposure from bivalves consumption.

Microplastics in canned, salt-dried, and instant sea cucumbers sold for human consumption

Determining the amount of microplastics (MPs) in food is key to clarifying their potential toxicity to humans. Here, we collected canned, instant, and salt-dried sea cucumbers Apostichopus japonicus, the most valued sea cucumbers, from Chinese markets to determine their content of MPs. Sea cucumbers contained MPs in the range of 0-4 MP individual^-1, an average of 1.44 MP individual^-1, and 0.081 MP g^-1. Accordingly, consuming 3 g of sea cucumbers could result in an exposure risk of an average of 0.51 MPs, 0.135 MPs, and 0.078 MPs day^-1 for canned, instant, and salt-dried sea cucumbers, respectively. MPs were in size range of 12-575 μm, and fibrous shape was dominant. Furthermore, among the five polymers identified, polypropylene showed the highest energy binding with two catalysts engaged in organic chemical oxidation. This study extends the knowledge regarding MPs occurrence in food and provides a theoretical basis for MPs toxicity in humans.

Occurrence and distribution characteristics of aged microplastics in the surface water, sediment, and crabs of the aquaculture pond in the Yangtze River Delta of China

The artificial breeding of freshwater crabs in China has become the main source, accounting for 45.69 % of the total output in 2020. However, microplastics widely exist in ponds due to the addition of meals, and the aging and breakage of plastic tools, and people know little about the occurrence of microplastics in the environment and the tissues of crabs during the cultivation of crabs in ponds. In this study, the abundance and characteristics of microplastics in ponds and crabs were studied finely, and the types of microplastics produced by meals and tools and the aging degree of microplastics in different media were studied in a typical aquaculture experimental base in the Yangtze Estuary of China. After we digested all the samples, there were microplastics in the water, sediment, and inedible part of crabs and crab meals, mainly in fiber shape, with a particle size of 100~300μm, and they have a certain degree of aging. The abundance of microplastics in surface water ranges from 4.4 to 10.8 items/L, and that in sediment ranges from 28.6 to 54.3 items/100 g·dry weight sediments. The average abundance of microplastics in crabs was 23.9 ± 15.9 items/individual. The content of microplastics in crabs' intestinal tissue was the highest, followed by gills and hepatopancreas. At the same time, the microplastics found in crabs were positively correlated with crab body weight and negatively correlated with hepatopancreas index. The results show that in the process of artificial breeding pond feeding, microplastics will be released from the process of meals dissolving in water, and fall off due to wear and tear during the use of tools. Microplastics found in the water, sediments and the tissues of crabs were all aged. Humans have a risk of ingesting microplastics when they eat the tissues of nonedible parts of crabs.

Microplastic Contamination of Chicken Meat and Fish through Plastic Cutting Boards

Microplastic contamination was found in fish and chicken bought on the market, in food stores and in chain supermarkets in the Middle East with the contamination ranging from 0.03 ± 0.04 to 1.19 ± 0.72 particles per gram of meat in chicken and from 0.014 ± 0.024 to 2.6 ± 2.8 particles per gram in fish. Only one fish was found to be free of microplastic. The source of the microplastic was established to be the polythene-based plastic cutting board the food was cut on. More microplastic contamination was found in food cut from the bone than in cut fillets when the fillets themselves were prepared on surfaces other than plastic. Washing the fish and chicken before food preparation decreased but did not completely remove the microplastic contamination. The fate of the microplastic in grilled fish was studied. The mechanical properties of typical plastic cutting boards commercially used in the markets were investigated in the form of tensile, hardness, and wear tests. Overall, the plastic cutting boards showed similar wear rates.

Effects of Polystyrene Microplastics on Human Kidney and Liver Cell Morphology, Cellular Proliferation, and Metabolism

Microplastics have gained much attention due to their prevalence and abundance in our everyday lives. They have been detected in household items such as sugar, salt, honey, seafood, tap water, water bottles, and food items wrapped in plastic. Once ingested, these tiny particles can travel to internal organs such as the kidney and liver and cause adverse effects on the cellular level. Here, human embryonic kidney (HEK 293) cells and human hepatocellular (Hep G2) liver cells were used to examine the potential toxicological effects of 1 μm polystyrene microplastics (PS-MPs). Exposing cells to PS-MPs caused a major reduction in cellular proliferation but no significant decrease in cell viability as determined by the trypan blue assay in both cell lines. Cell viability remained at least 94% for both cell lines even at the highest concentration of 100 μg/mL of PS-MPs. Phase-contrast imaging of both kidney and liver cells exposed to PS-MPs at 72 h showed significant morphological changes and uptake of PS-MP particles. Confocal fluorescent microscopy confirmed the uptake of 1 μm PS-MPs at 72 h for both cell lines. Additionally, flow cytometry experiments verified that more than 70% of cells internalized 1 μm PS-MPs after 48 h of exposure for both kidney and liver cells. Reactive oxygen species (ROS) studies revealed kidney and liver cells exposed to PS-MPs had increased levels of ROS at each concentration and for every time point tested. Furthermore, quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis at 24 and 72 h revealed that both HEK 293 and Hep G2 cells exposed to PS-MPs lowered the gene expression levels of the glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and antioxidant enzymes superoxide dismutase 2 (SOD2) and catalase (CAT), thus reducing the potential of SOD2 and CAT to detoxify ROS. These adverse effects of PS-MPs on human kidney and liver cells suggest that ingesting microplastics may lead to toxicological problems on cell metabolism and cell-cell interactions. Because exposing human kidney and liver cells to microplastics results in morphological, metabolic, proliferative changes and cellular stress, these results indicate the potential undesirable effects of microplastics on human health.